Use of modified vasoactive intestinal peptides in the treatment of hypertension

ABSTRACT

The present invention is based on the discovery that a VIP having a binding preference for VPAC2 can provide long-acting blood pressure control synergistically with concomitant anti-hypertensive therapies. Accordingly, methods and compositions useful for the treatment and/or amelioration of hypertension are provided.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to and the benefit of U.S. Provisional Application No. 61/493,845, filed Jun. 6, 2011, which is herein incorporated by reference in its entirety.

FIELD OF THE INVENTION

The present invention relates to methods and pharmaceutical compositions for treating hypertension. More particularly, the present invention relates to treatment of hypertension using a combination of a modified vasoactive intestinal peptide (VIP) having a binding preference for the VPAC2 receptor and at least one anti-hypertensive drug.

DESCRIPTION OF THE TEXT FILE SUBMITTED ELECTRONICALLY

The contents of the text file submitted electronically herewith are incorporated herein by reference in their entirety: A computer readable format copy of the Sequence Listing (filename: ---).

BACKGROUND

Hypertension is a prevalent medical condition characterized by abnormally high blood pressure in the arteries. Approximately 65 million adults in the United States are affected by hypertension. See Egan et al., 2010, JAMA 303(20): 2043-2050. The condition also affects children and teens. Clinically, hypertension is defined as a systolic pressure of 140 mm Hg or higher and a diastolic pressure of 90 mm Hg or higher. Left untreated, high blood pressure increases the risk of cardiovascular complications such as aneurysm, heart attack, heart failure, as well as renal failure.

Current treatments for hypertension include lifestyle changes as well as drug therapy. The major classes of anti-hypertensive drugs include, for example, angiotensin converting enzyme (ACE) inhibitors, β1 receptor antagonists (beta adrenergic antagonists), calcium channel blockers, and diuretics. However, a significant number of hypertensive patients are resistant and do not respond to such drugs. Accordingly, there remains a continuing need for new methods of treating hypertension.

SUMMARY OF THE INVENTION

The present invention is based in-part on the discovery that a modified vasoactive peptide (VIP) having a binding preference for VPAC2 can provide long-acting blood pressure control synergistically with concomitant anti-hypertensive therapies. Accordingly, the present invention provides methods and compositions for treating hypertension comprising administering to a patient a VIP having a binding preference for VPAC2 and at least one anti-hypertensive drug.

In one aspect, the invention provides a method of treating hypertension in a patient, comprising administering to the patient a VIP having a binding preference for VPAC2 and at least one anti-hypertensive drug selected from a β1 receptor antagonist, an ACE inhibitor, and a calcium channel blocker. The present invention is useful in treating, for example, pulmonary hypertension, uncontrolled essential hypertension, or resistant hypertension. In some embodiments, the patient has chronic heart failure, and the modified VIP is an adjunctive therapy. In some embodiments, the invention comprises administering the VIP having a binding preference for VPAC2 to a patient under going treatment for hypertension, including treatment with one or more of a β1 receptor antagonist, an ACE inhibitor, and a calcium channel blocker.

The present invention contemplates the use of a modified VIP having a binding preference for VPAC2. In an embodiment, the modified VIP induces vasorelaxation in a patient. In another embodiment, the VIP having a binding preference for VPAC2 induces decrease of any one of systolic pressure, diastolic pressure, and mean arterial pressure.

The VIP having a binding preference for VPAC2 may further have one or more of the following features. For example, the disclosed VIP may be recombinantly or chemically modified at the N- and/or C-termini by addition of one or more amino acids, and/or by fusion to heterologous amino acid sequences. Such modifications may function to provide a modified receptor binding profile, a longer circulatory half-life or persistence in the body, and/or enhanced biological potency, when compared to the native 28 amino acid mature VIP.

In an embodiment, the disclosed VIP includes an N-terminal moiety that provides binding preference to VPAC2. For example, the modified VIP may include additional N-terminal amino acids, such as a single amino acid at the N-terminus (e.g., Met). In an embodiment, the disclosed VIP comprises the sequence MHSDAVFTDNYTRLRKOMAVKKYLNSILN (SEQ ID NO: 13). The disclosed VIP may alternatively have from 1 to 5 amino acid insertions, deletions, and/or substitutions (collectively with respect to SEQ ID NO:13).

In certain embodiments, the VIP having a binding preference for VPAC2 may include a heterologous fusion partner. In an embodiment, the disclosed VIP may be fused to at least one Elastin-Like-Peptide (ELP) component, which are described in detail herein. For example, the modified VIP may be fused (e.g., by recombinant means) to the N-terminus of an ELP.

In the treatment methods, the VIP having a binding preference for VPAC2 may be administered using any suitable route of administration, such as by subcutaneous injection. In certain embodiments, the modified VIP is administered about once per day or about once per week. In an embodiment, where the modified VIP has the amino acid sequence of SEQ ID NO:14, the modified VIP is administered at a dose of about 1 microgram to about 100 milligram per kilogram of body weight. In another embodiment, the modified VIP is administered at a dose of about 10 microgram to about 10 milligram per kilogram of body weight.

The present invention contemplates the use of one of more anti-hypertensive drugs in combination with a VIP having a binding preference for VPAC2. In an embodiment, the anti-hypertensive drug and the disclosed VIP are administered separately. The anti-hypertensive drug may be a β1 receptor antagonist, an ACE inhibitor, and/or a calcium channel blocker. In an embodiment, the β1 receptor antagonist is atenolol. In another embodiment, the ACE inhibitor is ramipril. In a further embodiment, the calcium channel blocker is amlodipine.

In various embodiments, it is contemplated that co-treatment of the VIP having a binding preference for VPAC2 and the anti-hypertensive drug produces synergistic, or additive effects, or otherwise unexpected therapeutic advantages.

In a further aspect, the present invention provides a pharmaceutical composition comprising a VIP having a binding preference for VPAC2 and at least one hypertensive drug selected from a β1 receptor antagonist, an ACE inhibitor, and a calcium channel blocker. In a specific embodiment, the composition is formulated for once per day dosing. In another embodiment, the composition is formulated for once per week dosing.

DESCRIPTION OF THE FIGURES

FIG. 1 shows the amino acid sequence of a modified VIP-ELP fusion protein (M-VIP-ELP1-120, SEQ ID NO: 14) having Met at the N-terminus and 120 ELP1 units (VPGXG, SEQ ID NO: 3) fused to the VIP at the C-terminus.

FIG. 2 shows the amino acid sequence of a modified VIP-ELP fusion protein (MAA-VIP-ELP1-120, SEQ ID NO: 15) having Met-Ala-Ala at the N-terminus, which is activatable to the natural mature VIP peptide, and 120 ELP1 units (VPGXG, SEQ ID NO: 3) fused to the VIP at the C-terminus.

FIG. 3 is a plasmid map of pPB1031, which encodes ELP1-120 for convenient production of recombinant fusions.

FIG. 4 depicts pPB1046 encoding an M-VIP-ELP1-120 (SEQ ID NO: 23) fusion protein. Primers (P0045, SEQ ID NO: 16, P0048, SEQ ID NO: 17, and P0065, SEQ ID NO: 18) for construction of the recombinant gene are shown.

FIG. 5 depicts pPB1047 encoding an MAA-VIP-ELP1-120 (SEQ ID NO: 24) fusion protein. Primers (P0066, SEQ ID NO: 19, P0064, SEQ ID NO: 20, P0067, SEQ ID NO: 21) for construction of the recombinant gene are shown.

FIG. 6 shows the in vitro activity of native VIP and VIP-ELP fusion proteins PB1046 and PB1047 for VPAC2 receptor.

FIG. 7 shows the in vitro activity of native VIP and VIP-ELP fusion proteins PB1046 and PB1047 for VPAC1 receptor.

FIG. 8 shows the in vivo effect of PB1047 on rat blood pressure. Left panel shows systolic blood pressure. Right panel shows diastolic blood pressure. VIP-ELP lowers blood pressure for over a 12 hour period.

FIG. 9 is a plasmid map of pPB1120, which encodes VIP-ELP1-120.

FIG. 10 shows the in vitro activity of native VIP and VIP-ELP fusion proteins PB1120 and PB1046 for VPAC1 receptor.

FIG. 11 shows the in vitro activity of native VIP and VIP-ELP fusion proteins PB1120 and PB1046 for VPAC2 receptor.

FIG. 12A shows the pharmacokinetic profile of the VIP-ELP fusion protein PB1120 in monkeys (n=3) following single subcutaneous injection of 3 mg/kg with linear axes. FIG. 12B shows the pharmacokinetic profile of the VIP-ELP fusion protein PB1120 with semi-logarithmic axes.

FIGS. 13A, 13B, and 13C show the average change in systolic, diastolic, and mean arterial pressure, respectively over 3 hr intervals in rats injected subcutaneously with PB1120 at 0.1 mg/kg, 1 mg/kg, or 5 mg/kg dosages. FIG. 13D shows the average heart rate of the subject rats over 3 hour intervals following administration of PB1120.

FIGS. 14A, 14B, and 14C show that dose-dependent sustained blood pressure control with PB1046 (Vasomera™) is independent of β adrenergic receptor function in spontaneously hypertensive rats.

FIGS. 15A, 15B, and 15C show that co-administration of PB1046 (Vasomera™) and the anti-hypertensives—atenolol, amlodipine, or ramipril results in enhanced therapeutic effects.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to methods and compositions that are useful in treating hypertension. More specifically, the present invention is based in part on the discovery that a VIP having a binding preference for VPAC2 can provide synergistic blood pressure control with concomitant anti-hypertensive therapies. Accordingly, the present invention provides specific advantages for treating hypertension such as sustained blood pressure control, enhanced efficacy of treatment, and/or reduced side effects. In some embodiments, the patient has congestive heart failure, and the VIP is an adjunctive therapy.

Vasoactive intestinal peptide (VIP) is a peptide hormone containing 28 amino acid residues. VIP exhibits a wide variety of biological actions including, for example, systemic vasodilation, hypotension, coronary dilation, bronchodilation, and increased cardiac output in animals and humans. More specifically, VIP has a beneficial effect on blood and pulmonary pressure and has great potential as a therapeutic agent for hypertension.

There are at least two receptors for VIP, including the Vasoactive Intestinal Peptide Receptor 1 (VPAC1) and the Vasoactive Intestinal Peptide Receptor 2 (VPAC2). These receptors bind both VIP and the related molecule pituitary adenylate cyclase-activating polypeptide (PACAP). Both receptors are members of the seven-transmembrane G-protein coupled receptor family. VPAC1 is distributed, for example, in the central nervous system (CNS), liver, lung, intestine and T-lymphocytes. VPAC2 is found, for example, in the CNS, pancreas, skeletal muscle, heart, kidney, adipose tissue, testis, and stomach.

Nonetheless, the short half-life of VIP renders the natural peptide impractical as a pharmaceutical agent. See Pozo D, et al., Peptides 28(9):1833-1846 (2007). Indeed, studies have shown that the half-life of VIP in blood is less than two minutes (Domschke et al., 1978, Gut 19: 1049-53; Burhol et al., 1978, Scand J Gastroent 13: 807-813). Further, the multitude of biological effects of VIP may complicate its development for any particular indication.

In various embodiments described herein, the present invention provides methods of treating hypertension in a patient, comprising administering an effective amount of a VIP having a binding preference for VPAC2 and one or more anti-hypertensive drugs, or administering a VIP having binding preference for VPAC2 to a patient undergoing treatment with one or more of a β1 receptor antagonist, an ACE inhibitor, and a calcium channel blocker. Forms of hypertension treatable with the present invention include pulmonary hypertension, uncontrolled essential hypertension, and resistant hypertension.

Pulmonary hypertension is a relatively rare but highly fatal disease characterized by progressive pulmonary arterial hypertension and increased thickening of smaller pulmonary arteries and arterioles, culminating in right ventricular (RV) failure (Said et al., 2007, Circulation 115: 1260-8). VIP has been linked to pulmonary and systemic circulation. With respect to the pulmonary vascular bed and its alterations in pulmonary hypertension, VIP relaxes pulmonary vascular smooth muscle from several mammalian species in vitro, neutralizes or attenuates the actions of endothelin and other vasoconstrictors, reduces hypoxic pulmonary vasoconstriction, and inhibits the proliferation of pulmonary vascular smooth muscle from patients with pulmonary hypertension. Furthermore, VIP is a cotransmitter of the physiological nonadrenergic, noncholinergic system of pulmonary vascular smooth muscle relaxation.

Uncontrolled essential hypertension is blood pressure that is consistently higher than normal when no cause for the high blood pressure can be found. Essential hypertension is the most prevalent hypertension type, affecting 90-95% of hypertensive patients (Carretero et al., 2000, Circulation 101: 329-35). Concentrations of VIP are decreased in stroke-prone, essential hypertensive rats (Mori et al., 1993, Jpn Heart J. 34: 785-94) and use of human VIP with sterically stabilized liposomes can normalize systemic arterial pressure in spontaneously hypertensive hamsters (Onyuksel et al., 2006, Peptides 27: 2271-5).

Resistant hypertension is a form of high blood pressure that does not respond to treatment (i.e., blood pressure remains high even when a combination of drugs is administered). The causes of poor blood pressure control are numerous. The most likely causes are volume overload either due to excess sodium intake, intolerance to medications, noncompliance and secondary hypertension (Graves J W, 2000, Mayo Clin Prac 75: 278-84).

Current treatments for hypertension include lifestyle changes as well as drug therapy. Of the non-pharmacological treatments for hypertension, weight reduction and salt restriction have been considered to be the most successful. However, a number of medications are available for those patients whose blood pressure cannot be maintained in an acceptable range by non-pharmacological means. The major classes of anti-hypertensive drugs include, for example, angiotensin converting enzyme (ACE) inhibitors, β1 receptor antagonists (beta adrenergic antagonists), calcium channel blockers, and diuretics.

Angiotensin Converting Enzyme (ACE) inhibitors block the production of angiotensin II, a hormone that normally causes vasoconstriction. As a result, the blood vessels dilate, and blood pressure is reduced. In addition, angiotensin II stimulates the release of aldosterone, a hormone which is responsible for sodium retention. Accordingly, ACE inhibitors also lower blood pressure by mimicking the effect of diuretics. Examples of ACE inhibitors include, for example, enalapril, captopril, fosinopril, lisinopril, moexipril, perindopril, quinapril, ramipril, and trandolapril.

β1 receptor antagonists (beta adrenergic antagonists) block norepinephrine and epinephrine (adrenaline) from binding to beta receptors on nerves, thereby reducing heart rate. As a result, the heart beats more slowly and with less force and blood pressure is reduced. In addition, β1 receptor antagonists also cause vasodilation, thus further reducing blood pressure. Examples of β1 receptor antagonists include acebutolol, atenolol, bisoprolol, metoprolol, nadolol, nebivolol, and propranolol.

Calcium channel blockers keep calcium from entering the muscle cells of the heart and blood vessels, resulting in lowered blood pressure. More specifically, calcium channel blockers relax and dilate blood vessels by affecting the muscle cells in the arterial walls. Calcium channel blockers include, for example, amlodipine, diltiazem, felodipine, isradipine, nicardipine, nifedipine, nisoldipine, and verapamil.

Diuretics cause the body to excrete water and salt. This leads to a reduction in plasma volume, thereby lowering systemic blood pressure. Diuretics include, for example, furosemide, hydrochlorothiazide, and spironolactone.

All of the aforementioned hypertensive drugs have side effects. Further, a significant number of hypertensive patients are resistant and do not respond to such drugs. The present invention is based on the discovery that an increase in efficacy of treatment and/or reduction of side effects can be achieved by co-treatment with a modified vasoactive intestinal peptide having a binding preference for VPAC2 and one of more anti-hypertensive drugs such as an angiotensin converting enzyme (ACE) inhibitor, a beta adrenergic antagonists, and a calcium channel blocker.

Vasoactive intestinal peptide (VIP) is a peptide hormone containing 28 amino acid residues and is produced in many areas of the human body including the gut, pancreas and suprachiasmatic nuclei of the hypothalamus in the brain. VIP exhibits a wide variety of biological actions including systemic vasodilation, hypotension, increased cardiac output, respiratory stimulation, hyperglycemia, coronary dilation, bronchodilation in animals and humans. VIP also affects the balance of the immune system.

VIP has an effect on several parts of the body. With respect to the digestive system, VIP may induce smooth muscle relaxation (lower esophageal sphincter, stomach, gallbladder), stimulate the secretion of water into pancreatic juice and bile, and cause inhibition of gastric acid secretion and absorption from the intestinal lumen. Its role in the intestine is to stimulate secretion of water and electrolytes, as well as dilating intestinal smooth muscle, dilating peripheral blood vessels, stimulating pancreatic bicarbonate secretion, and inhibiting gastrin-stimulated gastric acid secretion. These effects work together to increase motility. VIP has the function of stimulating pepsinogen secretion by chief cells.

VIP has been found in the heart and has significant effects on the cardiovascular system. It causes coronary vasodilation, as well as having a positive inotropic and chronotropic effect.

Mature VIP has 28 amino acid residues with the following sequence: HSDAVFTDNYTRLRKQMAVKKYLNSILN (SEQ ID NO: 22). VIP results from processing of the 170-amino acid precursor molecule prepro-VIP. Structures of VIP and exemplary analogs have been described in U.S. Pat. Nos. 4,835,252, 4,939,224, 5,141,924, 4,734,400, 4,605,641, 6,080,837, 6,316,593, 5,677,419, 5,972,883, 6,489,297, 7,094,755, and 6,608,174, each of which is hereby incorporated by reference in its entirety for all purposes.

A number of mutations to improve peptide stability against proteases etc. are detailed in the literature (see Onune et al., Eur. J. Pharm. Biopharm. 2009, which is hereby incorporated by reference in its entirety for all purposes). These modified VIP peptides may have an M17L substitution to prevent oxidation of Met, one or more substitutions selected from K15R, K20R and K21R to increase proteolytic stability, and/or a substitution selected from N24A and S25A to increase proteolytic/thermal stability. The present invention provides modified VIP peptides that include one or more of these modifications, and with additional VIP modifications described herein.

In various embodiments described herein, a modified VIP (e.g., comprising SEQ ID NO: 13) (or a functional analog as described herein) is provided. Generally, functional analogs of VIP, include functional fragments truncated at the N- or C-terminus by from 1 to 10 amino acids, including by 1, 2, 3, or up to about 5 amino acids (with respect to SEQ ID NO: 13). Such functional analogs may contain from 1 to 5 amino acid insertions, deletions, and/or substitutions (collectively) with respect to the native sequence (e.g., SEQ ID NO: 22), and in each case retaining the activity of the peptide (e.g., through VPAC2 binding). Such activity may be confirmed or assayed using any available assay, including an assay described herein, and including any suitable assay to determine or quantify an activity described in Delgado et al., 2004, Pharmacol. Reviews 56(2):249-290. In these or other embodiments, the VIP component of the modified VIP of the invention has at least about 50%, 75%, 80%, 85%, 90%, 95%, or 97% identity with the native mature sequence (SEQ ID NO: 13). The determination of sequence identity between two sequences (e.g., between a native sequence and a functional analog) can be accomplished using any alignment tool, including that described in Tatusova et al., 1999, FEMS Microbiol Lett. 174:247-250.

In one aspect, the present invention provides a modified VIP molecule having receptor preference for VPAC2, as compared to unmodified VIP (e.g., a peptide consisting of the amino acid sequence of SEQ ID NO: 22). For example, the modified VIP may have a relative binding preference for VPAC2 over VPAC1 of at least about 2:1, about 5:1, about 10:1, about 25:1, about 50:1, about 100:1, about 500:1 or more. For example, in certain embodiments, the modified VIP activates the VPAC2 receptor substantially as mature, unmodified, human VIP, that is, with an EC50 within a factor of about 2 of mature, unmodified, human VIP (SEQ ID NO: 22). However, this same modified VIP is 50- or 100-fold or more less effective than mature, unmodified, human VIP in activating the VPAC1 receptor.

Such modified VIP molecules may contain modified N-terminal regions, such as an addition of from 1 to about 500 amino acids to the N-terminal histidine of VIP, which may include heterologous mammalian amino acid sequence. For example, the modified VIP may contain a single methionine at the N-terminal side of the natural N-terminal histidine of mature VIP. This molecule is also conveniently prepared in E. coli or other bacterial expression system, since the methionine will not be removed by E. coli when the adjacent amino acid is histidine. Alternatively, the N-terminal amino acid may be any of the naturally-occurring amino acids, namely alanine, arginine, asparagine, aspartic acid, cysteine, glutamic acid, glutamine, glycine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, serine, threonine, tryptophan, tyrosine, valine, and proline.

The additional sequence added to the N-terminus of VIP may be of any sequence, including biologically active and biologically inert sequences of from 1 to about 100, 1 to about 50, 1 to about 20, 1 to about 10, and 1 to about 5 amino acids.

The N-terminus of the modified VIP may have the structure M-N, where M is methionine, and N is the N-terminus of the VIP molecule (e.g., SEQ ID No. 14, FIG. 1). This methionine supports translation of the protein in a bacterial or eukaryotic host cell. Thus, the modified VIP can be made in a biological system, including bacterial and yeast expression systems (e.g., E. coli). While methionine can sometimes be removed by methionine aminopeptidase (MA) in bacterial expression systems, histidine (H) is one of the least favored residues at position 2 for MA.

In still other embodiments, the N-terminus is modified by fusion with a mammalian heterologous protein, such as a mammalian protein effective for extending half-life of therapeutic molecules. Such sequences may be mammalian sequences, such as albumin, transferrin, or antibody Fc sequences. Such sequences are described in, for example, U.S. Pat. No. 7,238,667 (particularly with respect to albumin conjugates), U.S. Pat. No. 7,176,278 (particularly with respect to transferrin conjugates), and U.S. Pat. No. 5,766,883, which are each hereby incorporated by reference in their entireties.

In these or other embodiments, N-terminal chemical modifications to the VIP N-terminus may provide receptor preference. Chemical modification of proteins and methods thereof are well known in the art. Non-limiting exemplary chemical modifications are PEGylation, methylglyoxalation, reductive alkylation, performic acid oxidation, succinylation, aminoethylation, and lipidation (Clifton, New Protein Techniques, New Jersey: Humana Press (1985) ISBX. 0-89603-126-8. Volume. 3 of. Methods in Molecular Biology). Chemical groups, such as PEGylation, may be attached by modifications of cysteine, methionine, histidine, lysine, arginine, tryptophan, tyrosine, and carboxyl groups, and have been described previously (see Lundblad, Techniques in Protein Modification, CRC Press (1995)).

Fusions to Bioelastic Polymers

In some embodiments, the VIP of the invention contains an N-terminal and/or C-terminal bioelastic polymer component. A “bioelastic polymer” may exhibit an inverse temperature transition. Bioelastic polymers are known and described in, for example, U.S. Pat. No. 5,520,672 to Urry et al. Bioelastic polymers may be polypeptides comprising elastomeric units of pentapeptides, tetrapeptides, and/or nonapeptides (e.g. “elastin-like peptides”). Bioelastic polymers that may be used to carry out the present invention are set forth in U.S. Pat. No. 4,474,851, which describes a number of tetrapeptide and pentapeptide repeating units that can be used to form a bioelastic polymer. Specific bioelastic polymers are also described in U.S. Pat. Nos. 4,132,746; 4,187,852; 4,500,700; 4,589,882; and 4,870,055. Still other examples of bioelastic polymers are set forth in U.S. Pat. No. 6,699,294, U.S. Pat. No. 6,753,311, and U.S. Pat. No. 6,063,061. The structures of such bioelastic polymers are hereby incorporated by reference.

In one embodiment, the bioelastic polymers are polypeptides of the general formula (VPGXG)_(m) where X is any amino acid (e.g., Ala, Leu, Phe) and m is from about 20 to about 2000, or about 50 to about 180. In exemplary embodiments, m is 60, 90, 120, 150, or 180. The frequency of the various amino acids as the fourth amino acid can be changed, as well as the identity of X.

For example, bioelastic polymers may comprise repeating elastomeric units selected from bioelastic pentapeptides and tetrapeptides, where the repeating units comprise amino acid residues selected from the group consisting of hydrophobic amino acid and glycine residues and where the repeating units exist in a conformation having a beta-turn of the formula:

wherein R₁-R₅ represent side chains of amino acid residues 1-5, and m is 0 when the repeating unit is a tetrapeptide or 1 when the repeating unit is a pentapeptide. Nonapeptide repeating units generally consist of sequential tetra- and pentapeptides. Hydrophobic amino acid residues are selected from alanine, valine, leucine, isoleucine, proline, phenylalanine, tryptophan, and methionine. In many cases, the first amino acid residue of the repeating unit is a residue of valine, leucine, isoleucine or phenylalanine; the second amino acid residue is a residue of proline; the third amino acid residue is a residue of glycine; and the fourth amino acid residue is glycine or a very hydrophobic residue such as tryptophan, phenylalanine or tyrosine. Particular examples include the tetrapeptide Val-Pro-Gly-Gly, the tetrapeptide GGVP, the tetrapeptide GGFP, the tetrapeptide GGAP, the pentapeptide Val-Pro-Gly-Val-Gly, the pentapeptide GVGVP, the pentapeptide GKGVP, the pentapeptide GVGFP, the pentapeptide GFGFP, the pentapeptide GEGVP, the pentapeptide GFGVP, and the pentapeptide GVGIP. See, e.g., U.S. Pat. No. 6,699,294.

In certain exemplary embodiments, the VIP of the invention contains an N-terminal and/or C-terminal ELP component. The ELP component comprises or consists of structural peptide units or sequences that are related to, or derived from, the elastin protein. Such sequences are useful for improving the properties of therapeutic proteins in one or more of bioavailability, therapeutically effective dose and/or administration frequency, biological action, formulation compatibility, resistance to proteolysis, solubility, half-life or other measure of persistence in the body subsequent to administration, and/or rate of clearance from the body. See, for example, International Patent Publication No. WO 2008/030968 which is hereby incorporated by reference in its entirety.

When the ELP is positioned at the C-terminus of VIP, additional modifications may be made at the VIP N-terminus, such as the addition of one or more amino acids, as described above. In alternative embodiments, there are no such modifications at the VIP N-terminus.

The ELP component is constructed from structural units of from three to about twenty amino acids, or in some embodiments, from four to ten amino acids, such as five or six amino acids. The length of the individual structural units, in a particular ELP component, may vary or may be uniform. In certain embodiments, the ELP component is constructed of a polytetra-, polypenta-, polyhexa-, polyhepta-, polyocta, and polynonapeptide motif of repeating structural units. Exemplary structural units include units defined by SEQ ID NOS: 1-12 (see below), which may be employed as repeating structural units, including tandem-repeating units, or may be employed in some combination, to create an ELP effective for improving the properties of the therapeutic component. Thus, the ELP component may comprise or consist essentially of structural unit(s) selected from SEQ ID NOS: 1-12, as defined below.

The ELP component, comprising such structural units, may be of varying sizes. For example, the ELP component may comprise or consist essentially of from about 10 to about 500 structural units, or in certain embodiments about 20 to about 200 structural units, or in certain embodiments from about 50 to about 150 structural units, or from about 75 to about 130 structural units, including one or a combination of units defined by SEQ ID NOS: 1-12. The ELP component may comprise about 120 structural units, such as repeats of structural units defined by SEQ ID NO: 3 (defined below). Thus, the ELP component may have a length of from about 50 to about 2000 amino acid residues, or from about 100 to about 600 amino acid residues, or from about 200 to about 500 amino acid residues, or from about 200 to about 400 amino acid residues.

In some embodiments, the ELP component, or in some cases the therapeutic agent, has a size of less than about 150 kDa, or less than about 100 kDa, or less than about 55 kDa, or less than about 50 kDa, or less than about 40 kDa, or less than about 30 or 25 kDa.

In some embodiments, the ELP component in the untransitioned state may have an extended, relatively unstructured and non-globular form so as to escape kidney filtration. In such embodiments, the therapeutic agents of the invention have a molecular weight of less than the generally recognized cut-off for filtration through the kidney, such as less than about 60 kDa, or in some embodiments less than about 55, 50, 45, 40, 30, or 25 kDa, and nevertheless persist in the body by at least 2-fold, 3-fold, 4-fold, 5-fold, 10-fold, 20-fold, or 100-fold longer than an uncoupled (e.g., unfused or unconjugated) therapeutic counterpart.

In these or other embodiments, the ELP component does not substantially or significantly impact the biological action of the therapeutic peptide. Thus, the VIP with ELP fusion of the present invention may exhibit a potency (biological action) that is the same or similar to its unfused counterpart. The VIP with ELP fusion of the present invention may exhibit a potency or level of biological action (e.g., as tested in vitro or in vivo) of from 10-100% of that exhibited by the unfused counterpart in the same assay. In various embodiments, the (activated) VIP with ELP fusion of the present invention may exhibit a potency or level of biological action (e.g., as tested in vitro or in vivo) of at least 50%, 60%, 75%, 80%, 90%, 95% or more of that exhibited by the unfused counterpart.

In certain embodiments, the ELP component undergoes a reversible inverse phase transition. That is, the ELP components are structurally disordered and highly soluble in water below a transition temperature (Tt), but exhibit a sharp (2-3° C. range) disorder-to-order phase transition when the temperature is raised above the Tt, leading to desolvation and aggregation of the ELP components. For example, the ELP forms insoluble polymers, when reaching sufficient size, which can be readily removed and isolated from solution by centrifugation. Such phase transition is reversible, and isolated insoluble ELPs can be completely resolubilized in buffer solution when the temperature is returned below the Tt of the ELPs. Thus, the therapeutic agents of the invention can, in some embodiments, be separated from other contaminating proteins to high purity using inverse transition cycling procedures, e.g., utilizing the temperature-dependent solubility of the therapeutic agent, or salt addition to the medium. Successive inverse phase transition cycles can be used to obtain a high degree of purity. In addition to temperature and ionic strength, other environmental variables useful for modulating the inverse transition of the therapeutic agents include pH, the addition of inorganic and organic solutes and solvents, side-chain ionization or chemical modification, and pressure.

In certain embodiments, the ELP component does not undergo a reversible inverse phase transition, or does not undergo such a transition at a biologically relevant Tt, and thus the improvements in the biological and/or physiological properties of the molecule (as described elsewhere herein), may be entirely or substantially independent of any phase transition properties. Nevertheless, such phase transition properties may impart additional practical advantages, for example, in relation to the recovery and purification of such molecules.

In the practice of the present invention, the ELP component functions to stabilize or otherwise improve the VIP component in the therapeutic composition. Subsequent to administration of the coupled VIP-ELP construct to the patient in need of the VIP therapeutic agent, the VIP component and the ELP remain coupled with one another while the VIP is therapeutically active, e.g., for the treatment and/or amelioration of hypertension.

In certain embodiments, the ELP component(s) may be formed of structural units, including but not limited to:

-   -   (a) the tetrapeptide Val-Pro-Gly-Gly, or VPGG (SEQ ID NO: 1);     -   (b) the tetrapeptide Ile-Pro-Gly-Gly, or IPGG (SEQ ID NO: 2);     -   (c) the pentapeptide Val-Pro-Gly-X-Gly (SEQ ID NO: 3), or VPGXG,         where X is any natural or non-natural amino acid residue, and         where X optionally varies among polymeric or oligomeric repeats;     -   (d) the pentapeptide Ala-Val-Gly-Val-Pro, or AVGVP (SEQ ID NO:         4);     -   (e) the pentapeptide Ile-Pro-Gly-X-Gly, or IPGXG (SEQ ID NO: 5),         where X is any natural or non-natural amino acid residue, and         where X optionally varies among polymeric or oligomeric repeats;     -   (e) the pentapeptide Ile-Pro-Gly-Val-Gly, or IPGVG (SEQ ID NO:         6);     -   (f) the pentapeptide Leu-Pro-Gly-X-Gly, or LPGXG (SEQ ID NO: 7),         where X is any natural or non-natural amino acid residue, and         where X optionally varies among polymeric or oligomeric repeats;     -   (g) the pentapeptide Leu-Pro-Gly-Val-Gly, or LPGVG (SEQ ID NO:         8);     -   (h) the hexapeptide Val-Ala-Pro-Gly-Val-Gly, or VAPGVG (SEQ ID         NO: 9);     -   (I) the octapeptide Gly-Val-Gly-Val-Pro-Gly-Val-Gly, or GVGVPGVG         (SEQ ID NO: 10);     -   (J) the nonapeptide Val-Pro-Gly-Phe-Gly-Val-Gly-Ala-Gly, or         VPGFGVGAG (SEQ ID NO: 11); and     -   (K) the nonapeptides Val-Pro-Gly-Val-Gly-Val-Pro-Gly-Gly, or         VPGVGVPGG (SEQ ID NO: 12).

Such structural units defined by SEQ ID NOS:1-12 may form structural repeat units, or may be used in combination to form an ELP component in accordance with the invention. In some embodiments, the ELP component is formed entirely (or almost entirely) of one or a combination of (e.g., 2, 3 or 4) structural units selected from SEQ ID NOS: 1-12. In other embodiments, at least 75%, or at least 80%, or at least 90% of the ELP component is formed from one or a combination of structural units selected from SEQ ID NOS: 1-12, and which may be present as repeating units.

In certain embodiments, the ELP component(s) contain repeating units, including tandem repeating units, of the pentapeptide Val-Pro-Gly-X-Gly (SEQ ID NO: 3), where X is as defined above, and where the percentage of Val-Pro-Gly-X-Gly (SEQ ID NO: 3) pentapeptide units taken with respect to the entire ELP component (which may comprise structural units other than VPGXG (SEQ ID NO: 3)) is greater than about 75%, or greater than about 85%, or greater than about 95% of the ELP component. The ELP component may contain motifs having a 5 to 15-unit repeat (e.g. about 10-unit or about 12-unit repeat) of the pentapeptide of SEQ ID NO: 3, with the guest residue X varying among at least 2 or at least 3 of the structural units within each repeat. The guest residues may be independently selected, such as from the amino acids Val, Ile, Leu, Ala, Gly, and Trp (and may be selected so as to retain a desired inverse phase transition property). Exemplary motifs include VPGXG (SEQ ID NO: 3), where the guest residues are Val (which may be present in from 40% to 60% of structural units), Gly (which may be present in 20% to 40% of structural units, and Ala (which may be present in 10% to 30% of structural units). The repeat motif itself may be repeated, for example, from about 5 to about 20 times, such as about 8 to 15 times (e.g., about 12 times), to create an exemplary ELP component. The ELP component as described in this paragraph may of course be constructed from any one of the structural units defined by SEQ ID NOS: 1-12, or a combination thereof. An exemplary ELP component is shown in FIG. 1 fused to the C-terminus of VIP.

In some embodiments, the ELP units may form a β-turn structure that provides an elastin-like property (e.g., inverse phase transition). Exemplary peptide sequences suitable for creating a β-turn structure are described in International Patent Publication No. WO 1996/032406, which is hereby incorporated by reference in its entirety. For example, the fourth residue (X) in the elastin pentapeptide sequence, VPGXG (SEQ ID NO: 3), can be altered without eliminating the formation of a β-turn.

In certain embodiments, the ELP components include polymeric or oligomeric repeats of the pentapeptide VPGXG (SEQ ID NO: 3), where the guest residue X is any amino acid. X may be a naturally occurring or non-naturally occurring amino acid. In some embodiments, X is selected from alanine, arginine, asparagine, aspartic acid, cysteine, glutamic acid, glutamine, glycine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, serine, threonine, tryptophan, tyrosine and valine. In some embodiments, X is a natural amino acid other than proline or cysteine.

The guest residue X (e.g., with respect to SEQ ID NO: 3, or other ELP structural unit) may be a non-classical (non-genetically encoded) amino acid. Examples of non-classical amino acids include: D-isomers of the common amino acids, 2,4-diaminobutyric acid, α-amino isobutyric acid, A-aminobutyric acid, Abu, 2-amino butyric acid, γ-Abu, ε-Ahx, 6-amino hexanoic acid, Aib, 2-amino isobutyric acid, 3-amino propionic acid, ornithine, norleucine, norvaline, hydroxyproline, sarcosine, citrulline, homocitrulline, cysteic acid, t-butylglycine, t-butylalanine, phenylglycine, cyclohexylalanine, β-alanine, fluoro-amino acids, designer amino acids such as β-methyl amino acids, Ca-methyl amino acids, Nα-methyl amino acids, and amino acid analogs in general.

Selection of X may be independent in each ELP structural unit (e.g., for each structural unit defined herein having a guest residue X). For example, X may be independently selected for each structural unit as an amino acid having a positively charged side chain, an amino acid having a negatively charged side chain, or an amino acid having a neutral side chain, including in some embodiments, a hydrophobic side chain.

In still other embodiments, the ELP component(s) may include polymeric or oligomeric repeats of the pentapeptides VPGXG (SEQ ID NO:3), IPGXG (SEQ ID NO:5) or LPGXG (SEQ ID NO:7), or a combination thereof, where X is as defined above.

In each embodiment, the structural units, or in some cases polymeric or oligomeric repeats, of the ELP sequences may be separated by one or more amino acid residues that do not eliminate the overall effect of the molecule, that is, in imparting certain improvements to the therapeutic component as described herein. In certain embodiments, such one or more amino acids also do not eliminate or substantially affect the phase transition properties of the ELP component (relative to the deletion of such one or more amino acids).

The structure of the resulting ELP components may be described using the notation ELPk [X_(i)Y_(j)-n], where k designates a particular ELP repeat unit, the bracketed capital letters are single letter amino acid codes and their corresponding subscripts designate the relative ratio of each guest residue X in the structural units (where applicable), and n describes the total length of the ELP in number of the structural repeats. For example, ELP1 [V₅A₂G₃-10] designates an ELP component containing 10 repeating units of the pentapeptide VPGXG (SEQ ID NO:3), where X is valine, alanine, and glycine at a relative ratio of 5:2:3; ELP1 [K₁V₂F₁-4] designates an ELP component containing 4 repeating units of the pentapeptide VPGXG (SEQ ID NO:3), where X is lysine, valine, and phenylalanine at a relative ratio of 1:2:1; ELP1 [K₁V₇F₁-9] designates a polypeptide containing 9 repeating units of the pentapeptide VPGXG (SEQ ID NO:3), where X is lysine, valine, and phenylalanine at a relative ratio of 1:7:1; ELP1 [V₁A₈G₇-10] designates an ELP component containing 10 repeating units of the pentapeptide VPGXG (SEQ ID NO:3), where X is valine, alanine, and glycine at a relative ratio of 1:8:7; ELP1 [V-5] designates a polypeptide containing 5 repeating units of the pentapeptide VPGXG (SEQ ID NO:3), where X is exclusively valine; ELP1 [V-20] designates a polypeptide containing 20 repeating units of the pentapeptide VPGXG (SEQ ID NO:3), where X is exclusively valine; ELP2 [5] designates a polypeptide containing 5 repeating units of the pentapeptide AVGVP (SEQ ID NO:4); ELP3 [V-5] designates a polypeptide containing 5 repeating units of the pentapeptide IPGXG (SEQ ID NO:5), where X is exclusively valine; ELP4 [V-5] designates a polypeptide containing 5 repeating units of the pentapeptide LPGXG (SEQ ID NO:7), where X is exclusively valine. Such ELP components as described in this paragraph may be used in connection with the present invention to increase the therapeutic properties of the therapeutic component.

Further, the Tt is a function of the hydrophobicity of the guest residue. Thus, by varying the identity of the guest residue(s) and their mole fraction(s), ELPs can be synthesized that exhibit an inverse transition over a 0-100° C. range. Thus, the Tt at a given ELP length may be decreased by incorporating a larger fraction of hydrophobic guest residues in the ELP sequence. Examples of suitable hydrophobic guest residues include valine, leucine, isoleucine, phenylalanine, tryptophan and methionine. Tyrosine, which is moderately hydrophobic, may also be used. Conversely, the Tt may be increased by incorporating residues, such as those selected from the group consisting of: glutamic acid, cysteine, lysine, aspartate, alanine, asparagine, serine, threonine, glycine, arginine, and glutamine; preferably selected from alanine, serine, threonine and glutamic acid.

The ELP component in some embodiments is selected or designed to provide a Tt (under physiological conditions) ranging from about 10° C. to about 80° C., such as from about 35° C. to about 60° C., or from about 38° C. to about 45° C. In some embodiments, the Tt is greater than about 40° C. or greater than about 42° C., or greater than about 45° C., or greater than about 50° C. The transition temperature, in some embodiments, is above the body temperature of the subject or patient (e.g., >37° C.) thereby remaining soluble in vivo, or in other embodiments, the Tt is below the body temperature (e.g., <37° C.) to provide alternative advantages, such as in vivo formation of a drug depot for sustained release of the therapeutic agent. See, for example, US Patent Publication No. US 2007/0009602, which is hereby incorporated by reference in its entirety.

The Tt of the ELP component can be modified by varying ELP chain length, as the Tt generally increases with decreasing molecular weight (MVV). For polypeptides having a molecular weight of >100,000, the hydrophobicity scale developed by Urry et al. (International Patent Publication No. WO 1996/032406, which is hereby incorporated by reference in its entirety) provides one means for predicting the approximate Tt of a specific ELP sequence. However, in some embodiments, ELP component length can be kept relatively small, while maintaining a target Tt, by incorporating a larger fraction of hydrophobic guest residues (e.g., amino acid residues having hydrophobic side chains) in the ELP sequence. For polypeptides having a molecular weight of <100,000, the Tt may be predicted or determined by the following quadratic function: Tt=M₀+M₁X+M₂X² where X is the MW of the fusion protein, and M₀=116.21; M₁=−1.7499; M₂=0.010349.

While the Tt of the ELP component, and therefore of the ELP component coupled to a therapeutic component, is affected by the identity and hydrophobicity of the guest residue, X, additional properties of the molecule may also be affected. Such properties include, but are not limited to solubility, bioavailability, persistence, half-life, potency and safety of the molecule.

In the Examples section below, it is seen that the ELP-coupled VIP agent retains a significant amount of the native VIP's biological activity, relative to unfused forms of VIP. Additionally, it is shown that ELPs exhibit long half-lives. Correspondingly, ELPs can be used in accordance with the invention to substantially increase (e.g. by greater than 10%, 20%, 30%, 50%, 100%, 200% or more, in specific embodiments) the half-life of VIP, as conjugated with an ELP, in comparison to the half-life of the free (unconjugated) form of the therapeutic agent. The modified VIP having extended circulatory half-life may be administered from 1 to about 10 times per week, such as from 1 to about 5 times per week, or 1 to about 3 times per week. The modified VIP or pharmaceutical composition comprising the same may be administered about once daily, or about every other day, or about every third day, or about once a week (i.e. once weekly dosing).

A recombinantly-produced VIP fusion protein, in accordance with certain embodiments of the invention, includes the fusion component (e.g., ELP) and a VIP or an analog of VIP associated with one another by genetic fusion. For example, the fusion protein may be generated by translation of a polynucleotide encoding VIP or an analog of VIP cloned in-frame with the ELP component.

In certain embodiments, the ELP component and VIP or an analog of VIP can be fused using a linker peptide of various lengths to provide greater physical separation and allow more spatial mobility between the fused portions, and thus maximize the accessibility of VIP or an analog of VIP, for instance, for binding to its cognate receptor. The linker peptide may consist of amino acids that are flexible or more rigid. For example, a flexible linker may include amino acids having relatively small side chains, and which may be hydrophilic. Without limitation, the flexible linker may comprise glycine and/or serine residues. More rigid linkers may contain, for example, more sterically hindering amino acid side chains, such as (without limitation) tyrosine or histidine. The linker may be less than about 50, 40, 30, 20, 10, or 5 amino acid residues. The linker can be covalently linked to and between VIP or an analog of VIP and an ELP component, for example, via recombinant fusion.

The linker or peptide spacer may be protease-cleavable or non-cleavable. By way of example, cleavable peptide spacers include, without limitation, a peptide sequence recognized by proteases (in vitro or in vivo) of varying type, such as Tev, thrombin, factor Xa, plasmin (blood proteases), metalloproteases, cathepsins, and proteases found in other corporeal compartments. In some embodiments employing cleavable linkers, the fusion protein may be inactive, less active, or less potent as a fusion, which is then activated upon cleavage of the spacer in vivo. Alternatively, where the therapeutic agent is sufficiently active as a fusion, a non-cleavable spacer may be employed. The non-cleavable spacer may be of any suitable type, including, for example, non-cleavable spacer moieties having the formula [(Gly)_(n)-Ser]_(m), where n is from 1 to 4, inclusive, and m is from 1 to 4, inclusive. Alternatively, a short ELP sequence different than the backbone ELP could be employed instead of a linker or spacer, while accomplishing the necessary effect.

In still other embodiments, the therapeutic agent is a recombinant fusion having a therapeutic component flanked on each terminus by an ELP component. At least one of said ELP components may be attached via a cleavable spacer, such that the therapeutic component is inactive, but activated in vivo by proteolytic removal of a single ELP component. The resulting single ELP fusion being active, and having an enhanced half-life (or other property described herein) in vivo.

In other embodiments, the present invention provides chemical conjugates of a VIP or an analog of VIP and the ELP component. The conjugates can be made by chemically coupling an ELP component to VIP or an analog of VIP by any number of methods well known in the art (See e.g., Nilsson et al., 2005, Ann Rev Biophys Bio Structure 34: 91-118). In some embodiments, the chemical conjugate can be formed by covalently linking VIP or an analog of VIP to the ELP component, directly or through a short or long linker moiety, through one or more functional groups on the therapeutic proteinacious component, e.g., amine, carboxyl, phenyl, thiol or hydroxyl groups, to form a covalent conjugate. Various conventional linkers can be used, e.g., diisocyanates, diisothiocyanates, carbodiimides, bis (hydroxysuccinimide) esters, maleimide-hydroxysuccinimide esters, glutaraldehyde and the like.

Non-peptide chemical spacers can additionally be of any suitable type, including for example, by functional linkers described in Bioconjugate Techniques, Greg T. Hermanson, published by Academic Press, Inc., 1995, and those specified in the Cross-Linking Reagents Technical Handbook, available from Pierce Biotechnology, Inc. (Rockford, Ill.), the disclosures of which are hereby incorporated by reference, in their respective entireties. Illustrative chemical spacers include homobifunctional linkers that can attach to amine groups of Lys, as well as heterobifunctional linkers that can attach to Cys at one terminus, and to Lys at the other terminus.

In certain embodiments, relatively small ELP components (e.g., ELP components of less than about 30 kDa, 25 kDa, 20 kDa, 15 kDa, or 10 kDa), that do not transition at room temperature (or human body temperature, e.g., Tt >37° C.), are chemically coupled or crosslinked. For example, two relatively small ELP components, having the same or different properties, may be chemically coupled. Such coupling, in some embodiments, may take place in vivo, by the addition of a single cysteine residue at or around the C-terminus of the ELP. Such ELP components may each be fused to one or more therapeutic components, so as to increase activity or avidity at the target.

The present invention further provides pharmaceutical compositions comprising an effective amount of a modified VIP having a binding preference for VPAC2 and at least one anti-hypertensive drug, together with a pharmaceutically acceptable carrier, diluent, or excipient. Such pharmaceutical compositions are effective for treating or ameliorating hypertension, as described herein.

It is contemplated that each of the therapeutic agents may be administered per se as well as in various forms including pharmaceutically acceptable esters, salts, and other physiologically functional derivatives thereof. It is further contemplated that the therapeutic agents may be formulated solely, or together with other therapeutic agents. For example, the modified VIP having a binding preference for VPAC2 and the one or more anti-hypertensive drugs may be administered as a single formulation or as separation formulations.

The formulations of the therapeutic agent include those suitable for parenteral as well as non-parenteral administration. Exemplary administration modalities include oral, buccal, topical, nasal, pulmonary, subcutaneous, intramuscular, and intravenous, among others. Formulations suitable for parenteral administration are preferred.

The formulations comprising the therapeutic agent of the present invention may conveniently be presented in unit dosage forms and may be prepared by any of the methods well known in the art of pharmacy. Such methods generally include the step of bringing the therapeutic agents into association with a carrier which constitutes one or more accessory ingredients. Typically, the formulations are prepared by uniformly and intimately bringing the therapeutic agent into association with a liquid carrier, a finely divided solid carrier, or both, and then, if necessary, shaping the product into dosage forms of the desired formulation.

Formulations suitable for parenteral administration conveniently comprise a sterile aqueous preparation of the therapeutic agent, which preferably is isotonic with the blood of the recipient (e.g., physiological saline solution). Such formulations may include suspending agents and thickening agents or other microparticulate systems which are designed to target the therapeutic agent to the circulation or one or more organs. The formulations may be presented in unit-dose or multi-dose form.

In addition to the aforementioned ingredients, the formulations of this invention may further include one or more accessory ingredient(s) selected from diluents, buffers, flavoring agents, disintegrants, surface active agents, thickeners, lubricants, preservatives (including antioxidants), and the like.

While one of skill in the art can determine the desirable dose in each case (including a unit dose for depot administration), a suitable dose of the therapeutic agent having the amino acid sequence of SEQ ID NO:14 be in a range of about 1 microgram (μg) to about 100 milligrams (mg) per kilogram body weight of the recipient, or in a range of about 10 μg to about 50 mg per kilogram body weight, or in a range of about 10 μg to about 10 mg per kilogram body weight. The desired dose may be presented as one dose or two or more sub-doses administered at appropriate intervals throughout the dosing period (e.g., one week, two weeks, etc). These sub-doses can be administered in unit dosage forms, for example, containing from about 10 μg to about 500 mg, or from about 50 μg to about 200 mg, or from about 50 μg to about 100 mg of active ingredient per unit dosage form. Alternatively, if the condition of the recipient so requires, the doses may be administered as a continuous infusion.

The mode of administration and dosage forms will of course affect the therapeutic amount of the peptide active therapeutic agent that is desirable and efficacious for a given treatment application. For example, orally administered dosages can be at least twice, e.g., 2-10 times, the dosage levels used in parenteral administration methods. Depot formulations will also allow for significantly more therapeutic agent to be delivered, such that the agent will have a sustained release over time.

In accordance with certain embodiments of the invention, the VIP may be administered from 1 to about 10 times per week, such as from 1 to about 5 times per week, or 1 to about 3 times per week. The modified VIP or pharmaceutical composition comprising the same may be administered about once daily, or about every other day, or about every third day, or about once a week.

In certain embodiments, the modified VIP is administered parenterally, such as by subcutaneous or intramuscular injection. The administration may be a unit dose of the modified VIP as described herein.

The modified VIP, when administered parenterally, may be administered once per day, or once or twice per week, or from once to five times per month. In these embodiments, the modified VIP may be administered as a soluble fusion peptide, that persists in the circulation, as described herein, to provide sustained activity with relatively infrequent administration. The modified VIP may be administered as a drug depot, as also described herein, to provide a sustained release of fusion peptide into the circulation over time. See US Patent Application Publication No. 2007/0009602, which is hereby incorporated by reference.

The present invention provides methods of treating and/or ameliorating hypertension in a patient. In certain aspects, the invention is for use in combination therapy, whereby a modified vasoactive intestinal peptide having a binding preference for VPAC2 is administered to a patient undergoing therapy with one or more anti-hypertensive drugs such as an angiotensin converting enzyme (ACE) inhibitor, a β1 receptor antagonist, and/or a calcium channel blocker.

Co-administration of the modified VIP and the one or more anti-hypertensive drugs can be by concomitant administration of a single formulation or of separate formulations, e.g., a modified VIP formulation and a formulation of one or more anti-hypertensive drugs. Co-administration does not require the therapeutic agents to be administered simultaneously. Administration of separate formulations is considered “concomitant” if the timing of their administration is such that the pharmacological activities of the modified VIP and the one or more anti-hypertensive drugs overlap in time, thereby exerting a combined anti-hypertensive effect in the patient. Accordingly, the modified VIP with a binding preference for VPAC2 may be administered prior to, at the same time, or after the administration of the one or more anti-hypertensive drugs. Co-administration also does not require the therapeutic agents to be administered by the same route of administration. Rather, each therapeutic agent can be effected by any appropriate route. For example, the modified VIP may be administered subcutaneously while the calcium channel blocker may be administered orally.

The co-administration of the modified VIP with a binding preference for VPAC2 and the one or more anti-hypertensive drugs provides beneficial effects derived from the co-action of these therapeutic agents. It is contemplated that a VIP having a binding preference for VPAC2 can provide long-acting blood pressure control synergistically with concomitant anti-hypertensive therapies. Accordingly, the invention provides specific advantages such as sustained blood pressure control, enhanced efficacy of treatment, and/or reduced side effects.

The present invention is further illustrated by the following examples that should not be construed as limiting. The contents of all references, patents, and published patent applications cited throughout this application, as well as the Figures, are incorporated herein by reference in their entirety for all purposes.

EXAMPLES Example 1 Cloning of VIP-ELP Constructs

The DNA sequence for the VIP peptide was as described in Simoncsits et al. (Eur. J. Biochem. 1988, 178(2):343-350, which is herein incorporated by reference in its entirety for all purposes), except that residue 17 was the native methionine and did not have either of the described C-terminal extensions.

Two initial variants were made, one with a methionine at the N-terminus, due to the required ATG start codon, (PB1046) and one with the tripeptide MAA at the N-terminus (PB1047). The methionine on PB1046 would normally be removed by methionine aminopeptidase (MA) but as histidine is the second residue and one of the least favored amino acids at this position for MA, the methionine is not removed. The methionine on PB1047 was removed to leave AA, which can then be removed in vitro or in vivo by DPPIV to give the histidine as the N-terminal residue. The VIP DNA sequence was cloned into vector pPB1031 (see FIG. 3) carrying the ELP1-120 DNA sequence to give an expression cassette under the control of the T7 promoter.

The synthetic oligonucleotides P0045, P0048, P0064 and P0065 were annealed together, digested with the restriction enzyme XbaI and ligated into the plasmid pPB1031 which had been digested with the restriction enzymes XbaI/KpnI to give expression plasmid pPB1046 (see FIG. 4).

The synthetic oligonucleotides P0066, P0064, P0067 and P0065 were annealed together, digested with the restriction enzyme XbaI and ligated into the plasmid pPB1031 which had been digested with the restriction enzymes XbaI/KpnI to give expression plasmid pPB1047 (see FIG. 5).

Example 2 Activity of Modified VIP-ELP Fusion Protein In Vitro

To measure the in vitro biological activity and potency of VIP or VIP-ELP fusion proteins, a cell-based bioassay was used. The assay measures the increase in intracellular cyclic adenosine monophosphate (cAMP) concentration in response to treatment with VIP or VIP-ELP fusion proteins in Chinese Hamster Ovary (CHO) cells that have been engineered to express either the human Vasoactive Intestinal Peptide Receptor 2 (VPAC2) or the human Vasoactive Intestinal Peptide Receptor 1 (VPAC1). Both VIP and VIP-ELP fusion proteins can stimulate production of cAMP in these cells, indicating that the fusion proteins retain the ability to bind and activate the receptor. Since the amount of cAMP accumulation in cells after receptor-mediated ligand binding and activation is directly proportional to the amount of intact peptide or fusion protein present, the assay can be used to determine bioactivity and relative potency.

In this example, the activity of VIP-ELP fusion proteins PB1046 and PB1047 was tested. Construct PB1046 contains VIP with a Met at the N-terminus and construct PB1047 contains VIP with Ala-Ala at its N-terminus. Both constructs have ELP(1-120) at their C-terminus. In the first experiment, the activity of the constructs was tested using CHO cells expressing the VIP receptor VPAC2. After 30 minute incubations of various concentrations of the fusion proteins with the cell, the cells were lysed and the amount of cAMP produced was measured using a commercial kit. PB1047 was DPP-IV treated prior to the addition to the cells. FIG. 6 shows the result. As shown, modified VIP fusion protein PB1046 is somewhat more active than native VIP protein, while PB1047 is less active.

The activity of PB1046 and PB1047 was also tested using CHO cells expressing the VIP receptor VPAC1. After 30 minute incubations of various concentrations of the fusion proteins with CHO cells, cells were lysed and the amount of cAMP produced was measured using a commercial kit. PB1047 was DPP-IV treated prior to the addition to the cells. FIG. 7 shows the result. This time, modified VIP fusion protein PB1046 is much less active than native VIP protein, while the relative activity of PB1047 against native VIP is about the same as it was in the test for VPAC2 receptor. These results suggest that PB1046 selectively activates VPAC2 receptor over VPAC1 receptor.

Example 3 Blood Pressure Effect of VIP-ELP Fusion Protein

The activity of the modified VIP-ELP fusion protein PB1047 was also tested in vivo. Specifically, effects of VIP-ELP fusion protein on blood pressure were tested. Spontaneously hypertensive rats were treated subcutaneous with PB1047 (10 mg/kg) or buffer control and their blood pressures were measured at several points after administration of the fusion protein. Five animals were used for each group and the graphs show the average and the standard deviation. PB1047 significantly reduced systolic and diastolic blood pressure in these animals for at least 12 hours post administration (see FIG. 8), indicating that the VIP-ELP fusion protein is active, and can be potentially used as pharmaceuticals in treating VIP-related diseases.

Example 4 Cloning, Expression, and Analysis of an Additional VIP-ELP Fusion Protein, PB1120

The VIP DNA sequence was cloned into vector pPB1120 (see FIG. 9) carrying the ELP1-120 DNA sequence to give an expression cassette under the control of the T7 promoter. Next, the E. coli production strain BLR was transformed with the pPB1120 plasmid and grown in rich medium as described above. Samples of the resulting VIP-ELP1-120 fusion peptide, PB1120, were purified and analyzed via SDS-PAGE.

The activity of the PB1120 fusion peptide was tested in vitro. The activity was tested using an assay utilizing CHO cells expressing VIP receptor (VPAC1) as described above in Example 3. As FIG. 10 demonstrates, PB1120 was approximately 1.4 fold less active than the native VIP peptide on the VPAC1 receptor. By comparison, the construct PB1046 which contains an N-terminal methionine residue was approximately 11-fold less active than the native VIP peptide. Over the course of multiple experiments, PB1120 was anywhere from 1.4- to 6-fold less active than the native VIP peptide on the VPAC1 receptor.

FIG. 11 illustrates the activity of PB1120 for the VPAC2 receptor. Like the results seen for the VPAC1 receptor, PB1120 show slightly less activity (˜1.5 fold less) than the native VIP peptide for VPAC2. However, in contrast to the results seen with VPAC1, PB1046 was equipotent for VPAC2 as compared to the native peptide. Over the course of multiple experiments, PB1120 was anywhere from 1.5- to 7-fold less active than the native VIP peptide on the VPAC2 receptor.

Example 5 Pharmacokinetic Profile of Modified VIP-ELP Fusion Protein PB1120

In addition to the biological potency assays described above, the pharmacokinetic profile of the VIP-ELP fusion protein PB1120 was also examined. Monkeys were given single subcutaneous (SC) injections (dosed at 3 mg/kg) of PB1120 and plasma drug concentrations were measured daily over the course of one week. Three animals were used and the graphs show the average and the standard deviation. More than half of the initial dose of PB1120 remained in the circulation to day 4 (see FIGS. 12A and 12B, which illustrate the mean plasma concentrations of PB1120 after SC administration using linear and semi-logarithmic axes, respectively).

Based upon this data, there appears to be a prolonged absorption phase after subcutaneous administration of PB1120, consistent with slow absorption from the site of administration. The apparent elimination half-life (t %), based on the decay of plasma concentrations, ranged from 9.9 to 45.8 h and likely reflects the slow absorption rather than true elimination. These data indicate that the VIP-ELP fusion protein has a dramatically extended half-life in comparison to native VIP and can potentially be administered at extended intervals (e.g. may be administered about once daily, about every other day, about every third day, or about once weekly).

Example 6 Effects of Modified VIP-ELP Fusion Protein PB1120 on Blood Pressure

To measure the effects of the modified VIP-ELP fusion protein PB1120 on systolic, diastolic, and mean arterial blood pressure, rats were given single, subcutaneous injections of 0.1 mg/kg, 1 mg/kg, or 5 mg/kg of PB1120 and evaluated over 3-hr intervals. FIGS. 13A, 13B, and 13C show the average change in systolic, diastolic, and mean arterial pressure, respectively. FIG. 13D shows the average heart rate over 3 hr intervals following administration of PB1120. As FIGS. 13A-C demonstrate, rats injected with either 1 mg/kg or 5 mg/kg of PB1120 showed significant reductions in systolic, diastolic, and mean arterial pressure 9 hrs post-injection, indicating that VIP-ELP fusion protein PB1120 can potentially be administered for the purpose of treating or preventing hypertension in afflicted individuals.

Example 7 Blood Pressure Control with VPAC2-Selective VIP is Independent of β-AR Function

The natural vasoactive intestinal peptide (VIP) triggers potent vasodilatation by activating the G-protein-coupled VPAC1 and VPAC2 receptors; however, VIP's clinical utility is limited due to its short half-life and VPAC1-mediated side-effects. Here, the effects of PB 1046 (Vasomera™) when given as a single-dose SQ bolus to conscious spontaneously hypertensive rats (SHR) was tested.

SHR rats (351±4 g, n=8) were instrumented for telemetric blood pressure and ECG monitoring. Via a Latin-Square design, the effects of Vasomera (1, 3, and 9 mg/kg SQ) as well as of vehicle (VEH, SQ) were evaluated. Finally, Vasomera™ (9 mg/kg SQ) was assayed during concomitant β-adrenergic receptor blockade (BB, atenolol 20 mg/kg/day PO). Changes in mean arterial pressure (MAP) and heart rate (HR) were measured.

Vasomera™ induced dose-dependent decreases in blood pressure that were sustained for up to 12 hours post-dosing (see FIG. 14A). For instance, at 9 mg/kg (177 nmol/kg), Vasomera™ lowered MAP by 16±3% (154±5 mmHg vs. 184±6 in VEH @+6 hr, P<0.05). Concomitantly, Vasomera™ triggered moderate cardio-acceleration (370±15 bpm at 9 mg/kg vs. 322±10 bpm in VEH @+2 hr, P<0.05). Notably, β-adrenergic receptor blockade blunted Vasomera™'s chronotropic effects (308±3 bpm @ +2 hr) while preserving/enhancing vaso-relaxation (MAP: 131±3 mmHg @ +6 hr) (see FIGS. 14B and 13C). No adverse clinical effects were noted.

These data suggest that Vasomera™ can provide long-acting blood pressure control synergistically with concomitant therapies (such as β-adrenergic receptor blockade) and may represent a novel adjunct therapeutic agent for resistant/uncontrolled hypertensive patients.

Example 8 Blood Pressure Control with VPAC2-Selective VIP in Conjunction with Anti-Hypertensives

The hemodynamic effects of Vasomera™ when given as a single-dose SQ bolus to conscious spontaneously hypertensive rats (SHR) pretreated with three common anti-hypertensives were tested.

SHR rats (351±4 g, n=8) were instrumented for telemetric BP and ECG monitoring. First, both Vasomera™ (9 mg [177 nmol]/kg, SQ) and placebo (VEH) were assayed in untreated animals. Then, the effects of Vasomera™ were tested during concomitant oral β-adrenergic receptor blockade (+BB, atenolol 20 mg/kg/day), calcium-channel blockade (+CCB, amlodipine 5 mg/kg/day) and ACE-inhibition (+ACE, ramipril 1 mg/kg/day). Mean arterial pressure (MAP) and heart rate (HR) were measured/averaged over 24 hours both pre- and post-dosing.

Vasomera™ induced potent decreases in blood pressure that were sustained for up to 12 hours post-dosing (see FIG. 15A). On average, Vasomera™ lowered MAP by 9±1% (188±6 to 171±5 mmHg, P<0.05). Vasomera™'s vaso-relaxation was preserved/enhanced in rats pre-treated with either atenolol (−14±1%, P<0.05), amlodipine (−13±2%, P<0.05), and/or ramipril (−9±2%, P<0.05) (see FIG. 15B). Vasomera™ triggered moderate cardio-acceleration in untreated rats (+8±1%, 355±6 to 384±8 bpm, P <0.05); such chronotropy was blunted under β-adrenergic receptor blockade (+6±1%, 278±2 to 294±2 bpm), but was unaffected by amlodipine or ramipril (see FIG. 15C). In all cases, heart rates were lower than in controls, and no adverse clinical effects were noted.

These results demonstrate that co-administration of Vasomera™ with concomitant anti-hypertensive therapies (e.g., β-adrenergic receptor blockade) can provide enhanced long-acting blood pressure control as well as reduced side effects.

Unless defined otherwise, all technical and scientific terms herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although any methods and materials, similar or equivalent to those described herein, can be used in the practice or testing of the present invention, the preferred methods and materials are described herein. All publications, patents, and patent publications cited are incorporated by reference herein in their entirety for all purposes.

The publications discussed herein are provided solely for their disclosure prior to the filing date of the present application. Nothing herein is to be construed as an admission that the present invention is not entitled to antedate such publication by virtue of prior invention.

While the invention has been described in connection with specific embodiments thereof, it will be understood that it is capable of further modifications and this application is intended to cover any variations, uses, or adaptations of the invention following, in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice within the art to which the invention pertains and as may be applied to the essential features hereinbefore set forth and as follows in the scope of the appended claims. 

1-32. (canceled)
 33. A method for treating hypertension in a patient, comprising administering to the patient: a vasoactive intestinal peptide (VIP) having a binding preference for the Vasoactive Intestinal Peptide Receptor 2 (VPAC2), and at least one anti-hypertensive drug, wherein the VIP comprises the amino acid sequence of SEQ ID NO: 13 with the N-terminal His at position 2, an N-terminal methionine, and an elastin-like peptide (ELP) at the C-terminus, wherein the ELP comprises at least 90 repeats of VPGXG (SEQ ID NO: 3) wherein X is V, A, and G in a ratio of about V5, A2, and G3, and wherein the VIP demonstrates an extended half-life in circulation.
 34. The method of claim 33, wherein said hypertension is selected from pulmonary hypertension, uncontrolled essential hypertension, pulmonary arterial hypertension, and resistant hypertension.
 35. The method of claim 33, wherein said vasoactive intestinal peptide induces vaso-relaxation.
 36. The method of claim 33, wherein said vasoactive intestinal peptide induces decrease of at least one of systolic pressure, diastolic pressure, and mean arterial pressure.
 37. The method of claim 33, wherein said elastin-like peptide component comprises 120 repeating units of VPGXG (SEQ ID NO: 3).
 38. The method of claim 37, wherein said vasoactive intestinal peptide has the amino acid sequence of SEQ ID NO:
 14. 39. The method of claim 33, wherein said vasoactive intestinal peptide and said anti-hypertensive drug are administered separately.
 40. The method of claim 33, wherein said vasoactive intestinal peptide is administered parenterally.
 41. The method of claim 40, wherein said vasoactive intestinal peptide is administered subcutaneously.
 42. The method of claim 33, wherein said vasoactive intestinal peptide is administered about once per day.
 43. The method of claim 33, wherein said vasoactive intestinal peptide is administered about once per week.
 44. The method of claim 33, wherein said vasoactive intestinal peptide has the amino acid sequence of SEQ ID NO:14 and is administered at a dose of about 1 microgram to about 100 milligrams per kilogram of body weight.
 45. The method of claim 44, wherein said vasoactive intestinal peptide is administered at a dose of about 10 micrograms to about 10 milligrams per kilogram of body weight.
 46. The method of claim 33, wherein said patient is a human patient.
 47. A pharmaceutical composition comprising a vasoactive intestinal peptide (VIP) having a binding preference for the Vasoactive Intestinal Peptide Receptor 2 (VPAC2), and at least one anti-hypertensive drug, wherein the VIP comprises the amino acid sequence of SEQ ID NO: 13 with the N-terminal His at position 2, an N-terminal methionine, and an elastin-like peptide (ELP) at the C-terminus, wherein the ELP comprises at least 90 repeats of VPGXG (SEQ ID NO: 3), and wherein the VIP demonstrates an extended half-life in circulation.
 48. The pharmaceutical composition of claim 47, wherein the composition is formulated for once per day dosing.
 49. The pharmaceutical composition of claim 47, wherein the composition is formulated for once per week dosing. 